xfrm: policy: split list insertion into a helper

... so we can reuse this later without code duplication when we add
policy to a second inexact list.

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 39d0db2a50d946556c28dae434acd00934374c3b..20d6815be0d74ca8246b898b847044751332d03e 100644 (file)
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -740,18 +740,12 @@ static bool xfrm_policy_mark_match(struct xfrm_policy *policy,
        return false;
 }
 
-int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
+static struct xfrm_policy *xfrm_policy_insert_list(struct hlist_head *chain,
+                                                  struct xfrm_policy *policy,
+                                                  bool excl)
 {
-       struct net *net = xp_net(policy);
-       struct xfrm_policy *pol;
-       struct xfrm_policy *delpol;
-       struct hlist_head *chain;
-       struct hlist_node *newpos;
+       struct xfrm_policy *pol, *newpos = NULL, *delpol = NULL;
 
-       spin_lock_bh(&net->xfrm.xfrm_policy_lock);
-       chain = policy_hash_bysel(net, &policy->selector, policy->family, dir);
-       delpol = NULL;
-       newpos = NULL;
        hlist_for_each_entry(pol, chain, bydst) {
                if (pol->type == policy->type &&
                    pol->if_id == policy->if_id &&
@@ -759,24 +753,41 @@ int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
                    xfrm_policy_mark_match(policy, pol) &&
                    xfrm_sec_ctx_match(pol->security, policy->security) &&
                    !WARN_ON(delpol)) {
-                       if (excl) {
-                               spin_unlock_bh(&net->xfrm.xfrm_policy_lock);
-                               return -EEXIST;
-                       }
+                       if (excl)
+                               return ERR_PTR(-EEXIST);
                        delpol = pol;
                        if (policy->priority > pol->priority)
                                continue;
                } else if (policy->priority >= pol->priority) {
-                       newpos = &pol->bydst;
+                       newpos = pol;
                        continue;
                }
                if (delpol)
                        break;
        }
        if (newpos)
-               hlist_add_behind_rcu(&policy->bydst, newpos);
+               hlist_add_behind_rcu(&policy->bydst, &newpos->bydst);
        else
                hlist_add_head_rcu(&policy->bydst, chain);
+
+       return delpol;
+}
+
+int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl)
+{
+       struct net *net = xp_net(policy);
+       struct xfrm_policy *delpol;
+       struct hlist_head *chain;
+
+       spin_lock_bh(&net->xfrm.xfrm_policy_lock);
+       chain = policy_hash_bysel(net, &policy->selector, policy->family, dir);
+       delpol = xfrm_policy_insert_list(chain, policy, excl);
+
+       if (IS_ERR(delpol)) {
+               spin_unlock_bh(&net->xfrm.xfrm_policy_lock);
+               return PTR_ERR(delpol);
+       }
+
        __xfrm_policy_link(policy, dir);
 
        /* After previous checking, family can either be AF_INET or AF_INET6 */